Drug Interaction Report

Futibatinib may increase the blood levels of idelalisib. This can increase the risk and/or severity of side effects such as liver problems, diarrhea, intestinal wall perforation, lung or breathing problems, and low white blood cell and platelet counts. You may need a dose adjustment or more frequent monitoring by your doctor to safely use both medications. Call your doctor immediately if you have fever, chills, joint pain or swelling, unusual bleeding or bruising, skin rash, itching, loss of appetite, fatigue, nausea, vomiting, abdominal pain, dark urine, pale stools, and/or yellowing of the skin or eyes, as these may be signs and symptoms of liver damage. Also let your doctor know if the number of bowel movements per day increases by six or more, or if you experience other potentially serious side effects such as infection, coughing, difficulty breathing, and shortness of breath. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.

Grapefruit juice can increase the blood levels of futibatinib. This may increase side effects including dry or inflamed eyes, inflamed cornea, increased tears, disorder of the retina, high phosphate levels in your blood, redness, swelling, peeling or tenderness, mainly on the hands or feet, nails separating from the bed or poor formation of the nail, urinary tract infection, constipation, diarrhea, dry mouth, abdominal pain, fatigue, muscle and joint pain, decreased levels of blood cells (white blood cells, red blood cells, and platelets), and changes in liver function blood tests. You should avoid the consumption of grapefruit and grapefruit juice during treatment with futibatinib. Be sure to take the medication at approximately the same time every day to maintain consistent blood levels and effects. Talk to your doctor or pharmacist if you have questions on how to take this or other medications you are prescribed. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.